Pump



June 8, 1943. L. s. MADLEM PUMP Filed May 6, 1940 2 Sheets-Sheet 1 LEOS. MADLEM.

A TTORNEVS.

Juhe 8, 1943. s. MADLEM PUMP Filed May 6, 1940 2 Sheets-Sheet 2 rINVCNTOR, 1.50 s. MADLEM.

ATTORNEYS.

Patented June 8, 1943 PUMP Leo S. Madlem, San Francisco, Calif.Application May 6, 1940, Serial No. 333,527

2 Claims.

This invention relates to pumps of the positive displacement type, andhas, among its objects, the provision of a rotary pump adapted for deepwell use; to provide a pump of the rotary vane typewherein the vanes arepositively driven by mechanical means, and are not required to be urgedoutwardly by resilient pressure; to provide a pump which may berelatively long in comparison with its diameter and may still beprovided with ade-.

quate ports to discharge longitudinally without undue friction losses;to provide a pump of the rotary vane type wherein the particular vane orrotary piston which is momentarily acting the impeller turns in positivecontact with the pump cylinder; to provide a pump of the type describedwhich is sufficiently well sealed so that it will produce a vacuum oftwenty-eight inches of mercury or over, and will operate sufficientlywell on a combination of water, steam, and air, to nable it to be usedas a wet vacuum pump; and to provide a pump having the characteristicsdescribed which can be cheaply and easily manufactured.

Other objects of my invention will be apparent or will be specificallypointed out in the description forming a part of this specification, butI do not limit myself to the embodiment of the invention hereindescribed, as various forms may be adopted within the scope of theclaims.

Referring to the drawings:

Fi l is a side elevation of a pump embodying my invention.

Fig. 2 is a vertical sectional view of the pump shown in Fig. l, theplane of section being indicated by the line 2-2 in the first figure.

Figs. 3 to 7 inclusive are transverse sectional views, the planes ofsection being the line in Fig. 2 carrying like numerals; and

Fig. 8 is a sectional view similar to Fig. 6 and showing a constructionwhich may be utilized to increase the area of the port normally used foroutlet.

Fig. 9 shows the outlet port in the form employed in connection with themodification of Fig. 8.

The nature of the invention may best be understood from a detaileddescription of the preferred form of the invention as shown in-thefigures, which show a pump of the deep well type. As viewed externallythe body I of the pump is preferably a cylindrical, cup-shaped casting,in the side of which are formed a plurality of small holes 3 whichcombine the functions of an intake port and a strainer. Secured to thetop of the pump body by any convenient means such as the screws is ahollow cap 1, whose open end is interiorly threaded to receive adischarge pipe 9. For the sake of completeness, a discharge spout II isshown as connecting to the upperv end of the discharge pipe 9, which isclosed by a bearing [3 for the drive-shaft l5 which transmits thenecessary power for the pump, traversing the length of the dischargepipe and, preferably, terminating within the pumpbody I.

The lower end, of the shaft I5 is journaled in a pairof bearings withinthe pump body, one of these bearings being formed as a boss Il formed onthe bottom of the pump body, and the other being a similar boss l9 whichis carried on a cover plate 2| clamped between the body I and the cap 1.These bearings may either be plain bearings as shown or may be bushed inaccordance with customary practice, the plain bearings being shown inthe present instance in order to keep the drawings as simple aspossible, it being understood that any suitable form may be used. Thebosses l7 and I9 are made accurately cylindrical and coaxial, but areeccentric with respect to the shaft as shown in all of the transversesectional views.

For a deep well pump it is convenient to make the pumping chamber 23within the body I approximately circular and concentric with the outersurface. The exact contour of the greater part of the inner wall ofthischamber is not particularly important; what is important is that thequadrant of this wall between the two points indicated by the referencecharacters 25 should be shaped so as to provide an accurate running fitwith the mechanically driven vanes, as will later be described, and thatthere should be provided a land 21, projecting into the chamber oppositethe quadrant just defined and having at least a portion of its innersurface also shaped to correspond with the motion of the vane tips. Theintake ports 3 are all locatedon one side of the pump chamber betweenthe quadrant 25, 25, and one side of the land 21.

Keyed or otherwise secured to the shaft I5 is a rotor drum 29, which issecured to the shaft by a web 3|, preferably located medially betweenthe ends of the pump chamber, and carrying -skirts 33 projecting aboveand below the central web for the full length of the cylinder to abearing with the top and bottom thereof, the diameter of the cylinderbeing such that it makes a running fit against the land 21. Opposedslots 35, extending longitudinally of the drum, are equally spaced aboutthe periphery thereof. Simplicity dictates that there should be four ofthese slots, corresponding with a four-vaned impeller, but it will beobvious that more could be used were it desirable for any reason to doso.

Pairs of vanes 31 and 39 are fitted into the slot, and bear against theedges thereof. Plain metal-to-metal bearings between the vanes and theimpeller drum give very satisfactory results, but I prefer to use insertstrips 4! to reduce wear and friction, and for use in water thesebearings strips may be made of rubber. Where the pump is to be used foroil, rubber is not satisfactory as the oil will attack it, and some ofthe synthetic oil resisting rubbers such as Neoprene, babbitt, oranti-friction bronzes or even hardened and polished steel may besubstituted.

The vanes 31 and 39 respectively of each pair are joined by a bridge 43,which carries at its center a scotch yoke 45 fitting over and driven bya respective one of the bosses i1 and is. It is preferable that thisdrive should be through a bushing 41, flattened on its two sides to bearupon the sliding faces 49 of the yoke, as this greatly lessens wear, butit is a refinement which may be omitted if desired, and the sides of theyoke may bear directly against the boss. It will be seen that the twopairs of vanes 31 and 39 are identical, but that their positions are inverted with respect to each other, the bridge 43 of one pair being atthe bottom of the cylinder so that the yoke engages the boss ll, whilethe bridge of the other pair is at the top (it the cylinder, and theyoke engages the boss I9.

It is obvious that rotation of the shaft will rotate the drum 33 andwith it the vanes 31 and 39. During this rotation the position of thevanes is at all times rigorously determined, in the plane of the vane bythe bearing of the scotch yoke against the eccentric bosses, and atright angles to the plane of the vanes by the edges of the slots 35.

Owing to the rigorous positioning of the blades, their ends sweep out aperfectly definite path which is very nearly, though not exactly.circular. Its departure from circularity, particularly over the quadrantopposite to the cutoff land and that including the land itself, is ofthe order of one tenth of one per cent, or, say, six thousandths of aninch in a pump where the vanes are five inches from tip to tip. For

cheaply made pumps, where relatively large clearances are permissible,the interior of the pump chamber can therefore be machined in ordinarylathes with the centers at the center of the bosses, and the smallvariations in clearance as the pump rotates are unimportant. Because ofthe fact that the vanes are not in pressure contact with the walls ofthe cylinders at any time, such clearances are not increased by wear,and it has been proved'possible to pull vacua of over twenty-eightinches with five inch diameter pumps of this character, without anyadditional seals to compensate for the lack of circularity.

Where clearances of the order mentioned are important, however there aretwo readily effective methods of effect such a seal. The first. and insome ways the simpler, is to insert rubber sealing strips 5|, similar tothe strips ll, in the ends of the blade, and such strips will readilycompress sufllciently to accommodate 'for the varying clearance, andgive a satisfactory seal at all times.

A more elegant solution, and one involving no approximations, is tomachine the inside of the barrel in accordance with the vane edge path.This can readily be accomplished on an automatic non-circular lathe, andit may be done on an ordinary machine lathe by setting the cutting toolin a scotch yoke and duplicating in efiect the action of the vanes tomachine out the cylinder.

It is possible, of course, to use the sealing strip ii in connectionwith such non-circular or quasi cardioid machining. The barrel 33 is ofsuch diameter as to make a runningflt with the land 21. Again, the fltis not exact, but is so nearly so that its departure from exactitudecannot be shown in the drawings, and the seal which it provides is, inpractice, entirely satisfactory.

Figure 8 show a modification of the invention in which the passageway 59is formed behind the land 21', to permit of greater area in the exhaustpassage 6| (see Fig. 9) where it is desirable to make the pump of smalldiameter and greater length, so as to increase capacity which may besatisfactorily utilized in a well of small diameter. Except for thefeature mentioned, this device i entirely similar in principle to thatalready described, and further explanation is believed unnecessary.

I claim:

l. A positive pressure pump for vertical operation comprising anapproximately cylindrical pump chamber having a top and bottom and alongitudinal cut-off land projecting into said chamber, circular bossesmounted on said top and bottom, midway between the top of said land andthe opposite side of the chamber, the top of the land and the oppositeside of said chamber having surfaces substantially concentric with saidbosses, a drive shaft journaled eccentrically in said bossessubstantially axially of said chamber and extending through said top, adrum having a plurality of opposed longitudinal slots therein extendingthe length of said chamber and secured to said shaft, and an impellervane fitting into each of said slots, a bushing on each of said bosses,said bushing having wherein said vanes have flexible edges in engagementwith the inner cylindrical wall of the pump chamber.

LEO S. MADLEM.

